South Coast Of Western Australia Research Articles

Find a match with triple-dating: Antarctic sub-ice zircon detritus on the modern shore of Western Australia

In this work we present a novel zircon triple-dating approach (Lu-Hf – U-Pb – (U-Th)/He), complimented with grain shape and trace element chemistry to test models of trans-continental transport of ultimately Gondwana interior derived detritus. Our integrated fingerprinting approach on single zircon grains provides the opportunity for robust source correlations as each isotopic system provides temporal constraints on distinct geological processes, ranging from source age (Lu-Hf), through crystallization age (U-Pb) to exhumation age ((U-Th)/He). Collectively, this detailed level of grain characterisation is much more diagnostic of source region than any single tracer alone, and together with grain shape, helps to constrain intermediate detrital grain histories between source and sink. Applying this approach to an enigmatic detrital zircon population from a modern beach sand on the south coast of Western Australia reveals a dominant 700-500 Ma U-Pb component, with a bimodal Hf-isotope composition and Silurian (U-Th)/He cooling age, all of which is strongly correlated with inferred sub-ice basement of East Antartica and the geodynamic setting of unexposed components of the Kuunga Orogen. Our work points towards multicycle sediment processing, and ongoing reworking of poorly known supra-Yilgarn Craton vestiges of Antarctica-derived sediment that became isolated during Cretaceous break-up of East Gondwana. Furthermore, Hf isotopes in these zircon grains suggest that the Kuunga Orogen in Antarctica was rooted on Archean crust.

Seasonal and interannual variability of the wave climate at a wave energy hotspot off the southwestern coast of Australia

Despite Australia having one of the most abundant offshore wave energy resources globally, there remains a lack of understanding of how this offshore resource extends into the coastal zone where most wave energy converters would be deployed. We used the phase-averaged wave model SWAN to simulate 38 years (1980–2017) of wave conditions near Albany, Western Australia, which has been proposed as a future commercial wave energy development site. The nearshore (30 m depth) wave resource varied seasonally and interannually with the wave energy flux and mean wave direction negatively correlated to the phase of the Southern Annular Mode (SAM) and positively correlated to the latitudinal position of the subtropical high-pressure ridge. As a result, the observed positive trend in SAM over recent decades may cause a decrease in nearshore wave energy (including fewer storm events) and an anti-clockwise (more southerly) rotation in wave direction. These changes may facilitate wave energy development and extraction by reducing the number and magnitude of extreme events during which wave energy cannot be extracted and equipment can be damaged. The interannual fluctuations in the wave resource can be significant and should be considered during the site selection for wave energy projects.

The performance of the three-float M4 wave energy converter off Albany, on the south coast of western Australia, compared to Orkney (EMEC) in the U.K.

In this study we compare wave climates and their potential for wave energy conversion for the two energetic but quite different sites of Albany and Orkney. Energy capture is based on the M4 machine with well defined characteristics. The M4 machine is a self reacting system with 3 floats, each float with a circular cross-section when viewed from above. The smaller two floats are rigidly connected by a beam, and the largest float is connected to the mid float by a beam with a hinge. The machine generates power through the relative angular motion of this hinge above the middle float. The machine performance was previously assessed for various locations in the eastern North Atlantic including the European Marine Energy Centre (EMEC) site west of the Orkney Islands, Scotland, for wave power output (Santo et al., 2016a) and extreme response (Santo et al., 2017). In this study, we apply the analysis to a location off Albany on the south coast of western Australia, an area well-known for almost continuous exposure to long period swells. We use Australian Department of Transport (DOT) wave buoy data measured in 60 m of water over the period 2009−2017. The hourly data is close to continuous but contains some gaps corresponding to ∼ 13% of the total duration, these are patched to form a continuous wave record.Having sized the machine based on mean wave period, extreme wave height statistical analysis is performed using storm-based identification and a peaks-over-threshold technique, following Santo et al. (2016b), providing information relevant for any wave energy converter at the location. From operability and power scheme economics, we then compare the optimal size of machine, practical power output and the associated variability in power produced by an M4 machine at Albany to the open North Atlantic location off the Orkneys. This is performed with the methodology outlined in Santo et al. (2016a). For survivability, it is important to identify extremes of machine motion. Hence, extreme responses are also compared for the central hinge angle of the machine in survival mode with the power take-off turned off. We find that a much larger machine is required at Albany, because of the longer waves compared to Orkney. However, at the two very different locations the power/cost ratios are similar.

The influence of particle size and mineralogy on both phosphorus retention and release by streambed sediments

In many streams worldwide including those on the south coast of Western Australia (WA), sediments of the > 2-mm fraction often contribute up to 50% of the streambed. However, most analysis and interpretation of sediment chemistry, including phosphorus (P), is conducted on the 2-mm fraction to P retention and release in sandy-gravely streams. Sediment samples were collected from streams in agricultural catchments, and P retention and release by the 2-mm (typically lateritic; iron rich) sediment fractions were examined using fluvarium and batch experiments. Phosphorus sorbed by sediment was estimated on a mass (mg P kg−1) and area basis (mg P m−2). Phosphorus sorption measurements suggested that mineralogy as well as particle size were important factors influencing P retention by stream sediments. Stream sediments retained approximately 30% of added P. In a desorption phase, approximately 8% of the retained P was released into stream water. Stream sediments in south western WA appear to be net immobilisers of P, retaining more P than they release, dependent on the stream P concentration. Exclusion of the > 2-mm fraction when determining stream sediment P dynamics may therefore underestimate whole stream sediment P retention and release.

Unexpected Southern Hemisphere ionospheric response to geomagnetic storm of 15 August 2015

Abstract. Geomagnetic storms are the most pronounced phenomenon of space weather. When studying ionospheric response to a storm of 15 August 2015, an unexpected phenomenon was observed at higher middle latitudes of the Southern Hemisphere. This phenomenon was a localized total electron content (TEC) enhancement (LTE) in the form of two separated plumes, which peaked southward of South Africa. The plumes were first observed at 05:00 UT near the southwestern coast of Australia. The southern plume was associated with local time slightly after noontime (1–2 h after local noon). The plumes moved with the Sun. They peaked near 13:00 UT southward of South Africa. The southern plume kept constant geomagnetic latitude (63–64° S); it persisted for about 10 h, whereas the northern plume persisted for about 2 h more. Both plumes disappeared over the South Atlantic Ocean. No similar LTE event was observed during the prolonged solar activity minimum period of 2006–2009. In 2012–2016 we detected altogether 26 LTEs and all of them were associated with the southward excursion of Bz. The negative Bz excursion is a necessary but not sufficient condition for the LTE occurrence as during some geomagnetic storms associated with negative Bz excursions the LTE events did not appear.

Are there conservation implications for kangaroos feeding on sea birds?

This research note documents an observation of a wild western grey kangaroo (Macropus fuliginosus) feeding on a dead silver gull (Chroicocephalus novaehollandiae) at Lucky Bay in the Cape Le Grand National Park on the south coast of Western Australia. Published evidence suggests that this behaviour is not unique and could be widespread in Western Australia and further afield. We consider why the kangaroo may be feeding on the dead gull and possible implications for conservation programs relying on poison meat baits to control introduced species.

The impact of fire on sand dune stability: Surface coverage and biomass recovery after fires on Western Australian coastal dune systems from 1988 to 2016

This study aims to determine the common response of coastal sand dunes in Western Australia (WA) to fire on decadal time-scales, in terms of ecological-geomorphic-climatic interactions to test the hypothesis that fire plays a role in coastal dune destabilisation. Fires are commonly suggested to have contributed to widespread dune reactivation in Australia and globally, a hypothesis that is relatively untested. We used data from the Landsat Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager missions to monitor changes in surface coverage on coastal sand dunes in south-west WA after fires. We analysed 31 fire scars from 1988 to 2016 in two Landsat scenes on the west and south coast of WA. Recovery ratios derived from the Normalised Difference Vegetation Index (NDVI) were used to monitor patterns in post-fire biomass and surface cover. Recovery ratios are correlated with indices of burn severity, and meteorological data to investigate relationships. We also used Maximum Likelihood Classification to monitor changes in bare sand area. Results suggest that recovery followed a strongly consistent pattern, and is characterised by rapid vegetation cover re-establishment within six to twelve months. Prior to this, some aeolian activity may have occurred but without substantial surface changes. Initial germination and/or resprouting were followed by steady growth up to seven years, where NDVI typically neared pre-fire values. Some variation in early recovery occurred between the west and south coast, possibly owing to relative proportions of reseeding and resprouting plants. A log regression explained 75% of the recovery pattern (79% on the south coast). Precipitation had some ability to explain recovery up to nine months post-fire (r2=0.29 to 0.54). No relationships were observed between estimates of burn severity and recovery. After nine months, the biggest cause of spatial variation in recovery was the pre-fire community composition and related seedbank or resprouting density. Image classification did not identify any new blowout features except where fires were not the primary cause. Results suggest that fires are not presently contributing to the destabilisation of coastal dunes in south-west WA.

Evaluation of spatiotemporal imputations for fishing catch rate standardization

As commercial fishing activity shifts to target different grounds over time, spatial gaps can be created in catch rate data, leading to biases in derived indices of fish abundance. Imputation has been shown to reduce such biases. In this study, the relative performance of several imputation methods was assessed using simulated catch rate data sets. Simulations were carried out for three fish stocks targeted by a commercial hook-and-line fishery off the southwestern coast of Australia: snapper (Chrysophrys auratus), West Australian dhufish (Glaucosoma hebraicum), and baldchin groper (Choerodon rubescens). For high-growth scenarios, the mean squared errors (MSEs) of geometric and linear imputations were lower, indicating higher accuracy and precision than that for base method (constant value) imputations. For low-growth scenarios, the lowest MSEs were achieved for base method imputations. However, for the final standardized and imputed abundance indices, the base method index consistently demonstrated the largest biases. Our results demonstrate the importance of selecting an appropriate imputation method when standardizing catch rates from a commercial fishery that has changed its spatial pattern of fishing over time.

Killer Whale (Orcinus orca) Predation on Beaked Whales (Mesoplodon spp.) in the Bremer Sub-Basin, Western Australia.

Observations of killer whales (Orcinus orca) feeding on the remains of beaked whales have been previously documented; however, to date, there has been no published account of killer whales actively preying upon beaked whales. This article describes the first field observations of killer whales interacting with, hunting and preying upon beaked whales (Mesoplodon spp.) on four separate occasions during 2014, 2015 and 2016 in the Bremer Sub-Basin, off the south coast of Western Australia.

Analysis of Water Dynamics in Banda Sea and its Influences on Continental Shelf Fishing Area

Over the rise of the Arafura Sea of the vertical configuration results shown curves which easy to understand about its water dynamics. The water character is oceanic’s as cool, salty and stable DO were maintaining by the variability of thermal structure in the continental shelf. The pattern of water masses is the current system surrounding the Banda Sea as an upwelling from undercurrent those enhances and nitrified the shelf. Along the coast of western part of Papua was conducted the parcel of water masses traveling across the fishing area where’s kind of fishing boat catches the fish in the whole year, and almost confining in the continental shelf has low current from the southern part. The current flows from west to east at the southern part of Nusa Tenggara Islands bringing water and curve to the southwestern coast of Australia. These water masses characterized the temperature, salinity and oxygen gradients from some points where may have an important implication to the slopes area between the deepest and the shallow water near the coast. The lower temperature ranges from 10.0˚C to 8.0˚C at 300m depth and 34.50‰ to 34.85‰ conducted was circulated back to the deepest layer were higher salinity and stable dissolved oxygen. This continental shelf as a fishing area boundary water dynamic may cause by these water dynamic, especially from data catches of the two fishing vessels catches 17,4 to 39,21kg/haul in the western area and 44.0 to 80kg/haul in eastern coast area.

The not-so-barren ranges

This is an impressionistic and informal essay written near the end of a novelist’s Australia Research Council funded research project: ‘Developing narratives from language and stories indigenous to the south coast of Western Australia’, and informed by how that research project morphed into an emphasis on revitalization of Noongar language, and the attempt to restore connections between a particular Creation Story and landscape in an area regarded as ‘massacre territory’. A sympathetic reader might think of the topic as ‘The Wirlomin Noongar Language and Stories Project meets The Barren Ranges’.

Long-term carbon storage and its recent loss in an estuarine Posidonia australis meadow (Albany, Western Australia)

Oyster Harbour, on the south coast of Western Australia, supports 3.6–3.9 km2 of seagrass meadows, following the loss of approximately 2.8–3.1 km2 in the 1980s. This small area of prevailing meadows hold significant carbon stores accumulated over the past 3000 years. In this study, we sampled three sediment cores from a Posidonia australis meadow and analysed organic matter (OM), organic carbon (OC) and inorganic carbon (IC) contents in bulk sediments, and δ13C signatures of OM. The OM and OC contents (mean ± SE) in the cores were 9.07 ± 0.36% and 2.24 ± 0.05%, respectively. The mean IC content was 3.16 ± 0.17%. δ13C signatures of the sedimentary OM ranged from −10.01‰ to −13.28‰. Using a Bayesian isotopic mixing model, it is estimated that 57–67% of the OM in the seagrass sediments was derived from P. australis detrital matter. The total carbon (TC) stores in 150 cm-thick seagrass sediments averaged 27.92 kg TC m−2 (10.79 kg OC m−2 and 17.13 kg IC m−2). Based on radiocarbon dating, the mean sediment accumulation rate was 0.0494 cm yr−1, which led to a long-term TC accumulation rate of 8.92 g TC m−2 yr−1 (3.45 g OC m−2 yr−1 and 5.47 g IC m−2 yr−1). Based on historical seagrass cover (3.6–6.7 km2 during the 1960s to 1980s), the estimated TC stores in 150 cm-thick seagrass sediments at Oyster Harbour would have been 101–187 Gg TC. The eutrophication-driven loss of seagrasses during the 1980s resulted in the absence of OC accumulation capacity amounting to 280–310 Mg OC (over 29 years). The loss of seagrass area could also have resulted in the release of 37–41 Gg CO2, assuming that all of the OC in shallow sediment is remineralised after meadow disturbance. These results exemplify the importance of seagrasses meadows as important carbon sinks and the potential for losses of carbon stores due to ecosystem degradation.

Taxonomic revision of Halimeda (Bryopsidales, Chlorophyta) in south-western Australia

Halimeda J.V.Lamour. is a green algal genus that is an important component of tropical reefs and lagoons. Although it does not generally occur outside the tropics, the range of one putatively widespread species, Halimeda cuneata Hering, in Western Australia extends southward past Cape Leeuwin to its southern extreme at Cape Howe and around to its most easterly record at Middle Island of the Recherche Archipelago. Previous molecular studies have shown that H. cuneata as recorded worldwide encompasses cryptic species diversity, with most of the cryptic entities being geographically isolated from the others. Halimeda cuneata has been the name consistently applied to specimens from the south-western coast of Australia, where it has been regarded as the only representative of its genus in the region. Using a combination of morphological features and assessment of species boundaries based on a plastid gene (tufA) and a nuclear protein-coding gene (HSP90), we have reassessed the supposed presence of H. cuneata in south-western Australia. Our results showed the existence of two species in the region, namely, H. versatilis J.Agardh, to which the name H. cuneata has been misapplied, and H. gigas W.R.Taylor, a central-Pacific species previously recorded only from tropical Australia.

The South African estuarine specialist Codium tenue (Bryopsidales, Chlorophyta) discovered in a south-western Australian estuary

Abstract Codium tenue, previously known reliably only from estuarine habitats in South Africa, is recorded from a similar habitat in the Walpole and Nornalup Inlet system, on the south coast of Western Australia. The Australian C. tenue has a repeatedly divaricately dichotomously branched thallus to 11.5 cm in height, with markedly compressed axes up to 1 cm in width at branch dichotomies, but distally attenuating to terete branch apices. Structurally, thalli have cortices with distinctive cuneate utricles up to 1310 μm long and 650 μm in diameter. Both the habit and structural morphology essentially agree with C. tenue as known in South Africa. Sequences generated from the Australian specimens are also wholly comparable with those of South African specimens newly generated in this study. While similarly disjunct South African/Western Australian distributions are known for other algae, that of C. tenue is particularly remarkable in that the species is apparently an estuarine specialist.

Extraordinary capture of a Randall's snapper Randallichthys filamentosus in the temperate south-eastern Indian Ocean and its molecular phylogenetic relationship within the Etelinae.

The capture of a rarely encountered Randall's snapper Randallichthys filamentosus (female, 587 mm fork length) from the upper continental slope (c. 350 m) off the south coast of Western Australia (c. 34·5° S; 122·5° E) in January 2014 represents its first record from the temperate Indian Ocean and a southern range extension. This record suggests that spawning of this predominantly tropical species may probably be occurring in the eastern Indian Ocean, considering the extensive, and unlikely, distance the progeny would have otherwise travelled from its typical distribution in the western and central Pacific Ocean.

Biochar and Compost Increase Crop Yields but the Effect is Short Term on Sandplain Soils of Western Australia

Sandplain soils on the south coast of Western Australia have low inherent fertility, which is mainly due to poor nutrient retention caused by insufficient clay and organic colloidal material. Previous research has shown the benefits in nutrient levels and retention from adding clay to sandplain soils; however, there is almost no information on the addition of organic amendments. A field experiment was established at the Esperance Downs Research Station, Western Australian, in May 2010, to assess the effects of wheat straw (WS) and chicken manure (CM) biochars and compost with and without phosphorus (P) addition on soil properties and crop production over five growing seasons. The five seasons alternated between winter and summer crops. The CM and WS biochar and compost treatments significantly increased crop yields and P uptake in 3, 2 and 1 of the five seasons, respectively. The yield increases (P « 0.05) were no more than 8%. By the end of the third season, no differences in crop yields were found that could be attributed to the organic amendments. The addition of P increased crop yields in each winter cropping season. Phosphorus addition explained more than 30% of the variation in crop yields. Despite marginal P levels and summer drought conditions, arbuscular mycorrhizal root colonisation was not affected by the organic amendments. There were no significant interactions between the organic amendments and P addition in terms of crop yields, P uptake or P uptake efficiency. We conclude that much of the effect of the organic amendments was due to direct nutrient addition which dissipated over time.

For a long time nothing happened: Settler colonialism, deferred action and the scene of colonization in Kim Scott’s That Deadman Dance

That Deadman Dance (2010) is Kim Scott’s third novel and his second to win the premier literary prize in Australia, the Miles Franklin Award. Scott’s novel is set in the period of contact between European settlers and the Indigenous Noongar people on the south coast of Western Australia at the beginning of the nineteenth century. Scott’s father was Noongar and his writing is positioned in the interplay between cultures and histories. In this article, I argue that contact fiction is conditioned by the psychoanalytic principle of deferred action and use Scott’s novel to exemplify this argument.

Malimup: A Tasmanian Aboriginal Hoabinhian site in the southwest of Western Australia?

The Hoabinhian technocomplex of Southeast Asia is characterised by distinctive pebble edge tools which are also found in Australia, but only in the southeast, including Tasmania. Charlie Dortch in the early 1970s reported a unique site with Hoabinhian tools in southwest Australia at Malimup, Western Australia (WA), dated to the recent past. An analysis of the pebble edge tools from Malimup showed they were similar to those from eastern Australia, which in turn were similar to the Southeast Asian ones. While it is possible that local Aboriginal people may have made these tools, it seems unlikely, given that no other such site has been found anywhere in WA. In considering the possibility that the site represents the presence of Aboriginal people from elsewhere in Australia during the early historical period, the most likely candidates are suggested to be Aboriginal women from Tasmania. Such women are documented as having lived with European sealers along the south coast of WA, and the site at Malimup is in a location suitable for a sealing camp, and near where sealers are reputed to have been active. It is further speculated that these tools may have been used for processing ochre, an activity of traditional significance to Tasmanian Aboriginal women, perhaps helping them come to terms with an unfamiliar environment. Such a suggestion may help shed light on the role of pebble tools elsewhere in Australia and indeed Southeast Asia.

Scaevola xanthina (Goodeniaceae), a new yellow-flowered species from the south coast of Western Australia

<i>Scaevola xanthina</i> (Goodeniaceae), a new yellow-flowered species from the south coast of Western Australia

Biology of the harlequin fish Othos dentex (Serranidae), with particular emphasis on sexual pattern and other reproductive characteristics

Key biological characteristics of the harlequin fish Othos dentex, a representative of a monospecific genus of the Anthiinae (Serranidae), were determined from samples collected around reefs on the south coast of Western Australia. The females of this relatively long-lived species (maximum recorded age in this study = 37 years) attained only a slightly greater maximum total length and age than males and neither the length nor the age-frequency distributions showed a conspicuous sex-based bimodality. Furthermore, gonads from a wide size and age range of O. dentex were shown by histology, at several locations along their length, to always comprise exclusively either ovarian or testicular tissues. Thus, O. dentex is a gonochorist, a sexual pattern only previously recorded definitively for one other anthiine serranid, i.e. Epinephelides armatus, which also occurs in south-western Australia. Similar to E. armatus, O. dentex possesses 'solid' testes with a central sperm duct, thereby differing in structure from those typically found in serranids, in which there is a central membrane-bound 'ovarian' lumen and peripherally located sperm sinuses. The gonadal characteristics and sexual pattern of these two gonochoristic anthiines are not consistent with a recent proposal for the trends exhibited by the evolution of gonochorism and protogyny within the Serranidae. Othos dentex has indeterminate fecundity and a protracted spawning period (7 months) and, on the basis of underwater observations and a low gonado-somatic index (I(G)) for males, is a pair spawner, which is unusual for a gonochorist of a serranid or member of a related family. While the large spots on the lower half of the body of O. dentex are shown quantitatively to be similarly yellow in juveniles and adult females, they then become blue in males at maturity and this intensifies during the spawning period, when they presumably play an important role in agonistic interactions among males and courtship with females. The attainment of maturity and rapid growth by O. dentex early in life may reflect selection pressures to reduce predation mortality during that period. Total mortality in the population is moderately low during later life, implying that the current fishing pressure on O. dentex is relatively light.